Engine malfunction protection

Abstract

A three-terminal module contains a relay with normally closed switch contacts and a delay circuit for the coil which opens the switch. The module switch contacts are wired between the engine ignition switch and the ignition coil of the engine. Malfunction detectors energize the delay, which eventually energizes the switch-operating coil, thereby stopping the engine. Opening and reclosing of the ignition switch enables the engine to restart.

I claim: 
     
       1. Apparatus for protecting an engine from malfunctioning, comprising: a unitary module having a single enclosure from which protrude only three functionally distinct electrical terminals,   the enclosure containing electrically interacting components consisting only of   a relay having normally closed switch contacts and a coil which responds to energization to open the contacts,   a delay circuit connected to the coil for delaying the energization of the coil,   the coil and delay circuit being connected between a first and second of the three terminals, and   the contacts being connected between the first and the third of the three terminals.   
     
     
       2. The apparatus of claim 1 further comprising means connected to the third terminal and responsive to deenergization to stop the engine. 
     
     
       3. The apparatus of claim 2 further comprising an ignition switch for the engine and also connected to the first terminal of the module. 
     
     
       4. The apparatus of claim 3 further comprising means connected to the second terminal of the module for sensing an engine malfunction, the sensing means having high electrical resistance when not sensing a malfunction and having low resistance when sensing a malfunction. 
     
     
       5. The apparatus of claim 4 further comprising a source of electrical energy connected in series with the ignition switch. 
     
     
       6. The apparatus of claim 5, wherein the sensing means includes a plurality of sensors connected in parallel to the second terminal. 
     
     
       7. The apparatus of claim 5, further comprising audio-visual indicator means connected between the first and second terminals. 
     
     
       8. The apparatus of claim 5 wherein the ignition switch is actuatable by a removable ignition key. 
     
     
       9. The apparatus of claim 6 wherein one sensor is connected by a wire to the second terminal and another sensor is connected by a wire to the one sensor. 
     
     
       10. In a system for operating an engine with electrical ignition, which system includes means requiring electrical energization in order for the engine to operate, a source of electrical energy, an ignition switch connected between the energy source and the energization requiring means, and at least one engine malfunction sensing means having high electrical resistance when not sensing a malfunction and having low resistance when sensing a malfunction: a single, unitary enclosure adapted to be mounted in the vicinity of the engine, said enclosure having only three electrical terminals protruding therefrom, and said enclosure containing only a relay having normally closed switch contacts and a coil which responds to energization to open the contacts, and a delay circuit connected to the coil for delaying the energization of the coil,   the coil and delay circuit being connected between a first and second of the three terminals, and   the malfunction sensing means being connected outside the enclosure to the second terminal,   the ignition switch being connected outside the enclosure to the first terminal, and   the energization requiring means being connected outside the enclosure to the third terminal,   whereby sensing of a malfunction causes the relay switch contacts to open after the delay provided by the delay circuit, thereby interrupting the supply of electrical energy from the source to the energization requiring means and opening and reclosing of the ignition switch causes reclosing of the relay switch contacts, thereby reestablishing the said supply of electrical energy to the energization requiring means.   
     
     
       11. The system of claim 10 wherein the energization requiring means is the ignition means of the engine.   
     
     
       12. The system of claim 10 wherein the delay circuit provides a delay of approximately 30 seconds.